June 17, 2019
1 min read

Model identifies ideal vancomycin concentrations for infants

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Photo of Amanda Gwee
Amanda Gwee

Researchers have developed a population-based pharmacokinetic model to identify target levels for vancomycin treatment so that infants infected with Staphylococcus aureus receive effective therapy.

Study researcher Amanda Gwee, DTMH, PhD, a general pediatrician, infectious disease physician and clinical pharmacologist from the Royal Children’s Hospital Melbourne, Australia, told Infectious Diseases in Children that the current approach to vancomycin treatment in infants is to measure the lowest level of the antibiotic in the blood, or the trough level.

However, “the effectiveness of vancomycin to treat S. aureus infections is not determined by the trough level but instead relates to the drug concentrations in blood over time, or area under the concentration-time curve (AUC),” she said.

Gwee and colleagues wrote that for adults with S. aureus infection, the pharmacodynamic target correlates with the ratio of the AUC over 24 hours (AUC24) to the minimum inhibitory concentration (MIC) of the bacteria above 400 — or AUC24/MIC>400.

To develop their model, Gwee and colleagues analyzed data from 104 infants who were enrolled in a randomized clinical trial of vancomycin. The trial occurred between Sept. 1, 2014, and Dec. 31, 2017.

The researchers found that the 48-hour trough concentrations that provided a 90% probability of target attainment were greater than 20 mg/L for a 6-hour dosage interval and greater than 15 mg/L for a 12-hour dosage interval. Importantly, the researchers developed a clinical tool that enables hospital staff to look up the vancomycin level required to achieve the target AUC for both premature and term infants.

“Our study helps clinicians understand the relationship between the trough level that we routinely measure and the drug exposure, which determines effectiveness of treatment,” Gwee said. “As a result, we have now identified new values for vancomycin trough levels that clinicians can target to ensure that all babies receive doses of vancomycin that will be effective to treat S. aureus infections.” – by Katherine Bortz

Disclosures: The authors report no relevant financial disclosures.